The tweetstorm came hours after Thomas Markle told TMZ that he would not stop talking to the press until his daughter agreed to see him.

Meghan Markle has come under heavy fire from her half-sister Samantha Markle just days after her father gave an in-depth interview to The Sun, in which he said his daughter looked terrified in her new role, and bemoaned being frozen out.

In a tweetstorm that started Tuesday night, Samantha said that if their father died it would be her royal relative's fault.

Posting a link to an article about Meghan and Prince Harry's appearance at the Nelson Mandela centenary exhibition in London earlier that day, Markle said: "How about you pay tribute to your own father?! Enough is enough."

"Act like a humanitarian act like a woman! If our father dies I'm holding you responsible, Meg!"